<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Hulk扩展</title>
  <style>
    body {
      width: 250px;
      padding: 20px;
      font-family: Arial, sans-serif;
      text-align: center;
      background-color: #f5f5f5;
      margin: 0;
    }
    h2 {
      color: #2c3e50;
      margin-top: 0;
      margin-bottom: 15px;
    }
    p {
      color: #7f8c8d;
      margin-bottom: 20px;
      line-height: 1.4;
    }
    button {
      background-color: #27ae60;
      color: white;
      border: none;
      padding: 10px 20px;
      font-size: 16px;
      border-radius: 5px;
      cursor: pointer;
      transition: background-color 0.3s;
    }
    button:hover {
      background-color: #229954;
    }
    button:active {
      transform: translateY(1px);
    }
  </style>
</head>
<body>
  <h2>改变背景颜色</h2>
  <p>点击下方按钮将当前页面背景色改为绿色</p>
  <button id="changeColor">改变颜色</button>
  <script src="popup.js"></script>
</body>
</html>